Heinrich Lenz: 1804-1865H Lenz.jpg

Lenz’s Law: direction of a magnetically induced current is such as to oppose the cause of the current.
Explains how electromagnetic circuits obey the law of conservation of energy.








When a magnet is dropped down a metal tube the falling magnet produces a induced current. This current moves in a Coducting tube.jpgcircular motion around the tube which creates its own vertical electric field inside the tube. This can result in one of two effects:
1) Attract the magnet causing it to fall faster and creating a greater induced current
2) Repel the magnet and oppose the motion causing it to fall faster


Induction: movement of charge caused by an external charged object; no contact.


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The left side of this ammeter becomes north because a opposing force is created by the bar magnet, repeling the bar magnet.
The induced magnetic field is to the left.









To see a demonstration of Lenz's Law click here

For further information:
http://ldindustries.ca/LDIndustries/P30/LangdalePhysics30.html